从didFinishPickingMediaWithInfo调用performSegueWithIdentifier

Question

I want to call programmatically a segue from the imagePickerController:didFinishPickingMediaWithInfo: method, but it doesn't work. It doesn't crash, but doesn't work. It just does nothing. The prepareForSegue method is called correctly.

- (void) imagePickerController:(UIImagePickerController *)picker 
         didFinishPickingMediaWithInfo:(NSDictionary *)info {

   rutaFoto = [info valueForKey:UIImagePickerControllerMediaURL];
   [self dismissModalViewControllerAnimated:YES];
   [self performSegueWithIdentifier:@"aGaleria" sender:self];
}

The segue links 2 UIViewControllers . And if I call the segue with performSegueWithIdentifier from other place (eg from a push UIButton method), it works. Any ideas?

Answer 1

Try using dismissViewControllerAnimated:completion: and put the call to performSegueWithIdentifier:sender: in the completion block (dismissModalViewControllerAnimated: is depreciated anyway, so you shouldn't be using it).

      [self dismissViewControllerAnimated:YES completion:^{
           [self performSegueWithIdentifier:@"aGaleria" sender:self]; 
      }];

Answer 2

I'm wondering if this is to do with the main thread already handling a change in the current ViewController, the transition between didFinishPickingMediaWithInfo to the original ViewController from which it was triggered from.

I'd try two things, the first is to put a delay when you call the aGaleria segue:

sleep(2.0);
[self performSegueWithIdentifier:@"aGaleria" sender:self];

The second, and much better option, is to perform the segue from the view AFTER you have finishedPickingMediaWithInfo. You could set up a new NSNotificationCenter trigger in the original ViewController and then trigger it with a delay in the didFinishPicking method: